GM announced the Spark EV back in October with little fanfare and few hard details. With the recent fires in the testing of the Volt, some car buyers and the government are looking at GM and specifically the batteries used in its vehicles.

The Volt is currently under investigation by the NHTSA and GM engineers to determine the cause of the fire and what should be done to prevent the fire from happening again. The battery packs in the Volt are made by LG Chem and use lithium-ion technology. That battery tech is more prone to fire than some other battery technology.

Business Week reports that GM has chosen another company and different battery tech for the Spark. The Spark will use batteries built by A123. The A123 batteries are less fire prone as they use lithium phosphate chemistry. When GM took bids years ago for the battery packs for the Volt, the technology to mass-produce lithium phosphate batteries was not available.

James Hall from consulting company 2953 Analytics stated, "Lithium phosphate chemistry looks like it could be more friendly in terms of heat management. But it stores less energy. There is a tremendous amount of new discovery. This is new territory for lithium batteries."

Robert Kanode is the CEO of battery maker Valence Technology Inc. in Austin, Texas. Kanode said that if his firm used phosphate batteries to build a pack for the Volt it would be about 10% larger than the existing Volt battery pack. This is another reason phosphate technology isn't common in EVs today.